1. Technical Field
The present invention relates to a semiconductor device. In particular, the present invention relates to a semiconductor device in which the dielectric constant of the low-dielectric-constant film is less than 3.9.
2. Related Art
Conventionally, an IGBT (Insulated Gate Bipolar Transistor) is known that includes a floating p region in a semiconductor device having a plurality of trench gates. A conventional semiconductor device uses a BPSG (Boron Phosphorous Silicon Glass) film in an inter-layer insulating film between the floating p region and an emitter electrode, as shown in Patent Document 1, for example.
Patent Document 1: Japanese Patent Application Publication No. 2006-245477
Patent Document 2: Japanese Patent Application Publication No. 2009-81385
Patent Document 3: Japanese Patent Application Publication No. 2005-57238
Patent Document 4: Japanese Patent Application Publication No. H5-243561
Patent Document 5: Japanese Patent Application Publication No. 2001-308327
Non-Patent Document 1: M. Yamaguchi et al., “IEGT Design Criterion for Reducing EMI Noise,” Proceedings of 2004 International Symposium on Power Semiconductor Devices & ICs, May 2004, pp. 115-118
Non-Patent Document 2: Y. Onozawa et al., “Development of the next generation 1200 V trench-gate FS-IGBT featuring lower EMI noise and lower switching loss,” Proceedings of the 19th International Symposium on Power Semiconductor Devices & ICs, 27th to 30th of May 2007, pp. 13-16
However, with an IGBT using conventional BPSG in the inter-layer insulating film, the potential of the floating p region draws near the potential of the emitter electrode. Specifically, in a conventional semiconductor device, a potential difference occurs between the floating p region and the gate electrode, and therefore there is a problem that when the semiconductor device is turned ON, a displacement current flows from the floating p region to the gate electrode.